# Base path

> Configure base paths in OpenAPI with `x-fern-base-path`. Set up endpoint prefixes like /v1 for your API definitions with Fern.

Use the `x-fern-base-path` extension to configure the base path prepended to every endpoint.

The example below configures the `/v1` base path so the full endpoint path is
`https://api.example.com/v1/users`.

```yaml title="Set the base path in openapi.yml" {1}
x-fern-base-path: /v1
servers:
  - url: https://api.example.com
paths:
  /users: ...
```